Hexamethylenediamine also referred to as 1,6-diaminohexane or 1,6-hexanediamine (abbreviated as HMD or HMDA) has the chemical formula H2N(CH2)6NH2. HMD is an important raw material in the chemical industry. HMD is used, for example, in the preparation of polyamides, polyureas or polyurethanes and copolymers of these materials. Cadaverine, also referred to as 1,5-diaminopentane, is used as a monomer for polyamine production. Putrescine, also referred to as 1,4-diaminobutane, is used as a monomer for polyamine production. Heptamethylenediamine, also referred to as 1,7-diaminoheptane, is used as a monomer for polyamine production. Ethylenediamine is used as a monomer for polyamine production as well as a precursor to other chemicals. Engineered microorganisms for fermentative production of these compounds and other diamines or their immediate precursors have been reported. Typically, processes for their fermentation and isolation require acids and bases that generate salt by-products.